Decorative resin molded articles with a decorative sheet laminated on the surface of a resin molded article have been used heretofore in vehicle interior and exterior components, building interior materials, housings for home electric appliances, and the like. In production of such a decorative resin molded article, for example, a molding method is used in which a decorative sheet given a design beforehand is integrated with a resin by injection molding. Typical examples of the molding method include an insert molding method in which a decorative sheet is molded into a three-dimensional shape beforehand by a vacuum molding die, the decorative sheet is inserted into an injection molding die, and a fluidized resin is injected into the die to integrate the resin with the decorative sheet, and an injection molding simultaneous decorating method in which a decorative sheet inserted into a die in injection molding is integrated with a molten resin injected into a cavity.
Decorative sheets to be used for production of decorative resin molded articles are required to have not only moldability but also a function of giving decorative resin molded articles contamination resistance with respect to various products that are used in the everyday life. Particularly, in recent years, skin care products such as sunscreen cosmetics, insect repellents and so on have tended to be often used, and thus the skin coated with such a skin care product has come into contact with decorative resin molded articles more frequently before. Accordingly, decorative sheets are strongly desired to have chemical resistance with respect to skin care products and so on.
Several techniques for imparting moldability and chemical resistance to a decorative sheet have been heretofore proposed. For example, Patent Document 1 discloses that when in a decorative sheet including a mold release layer and a surface protective layer in this order on one surface of a base material sheet, the surface protective layer is formed of an ionizing radiation curable resin composition which contains a polyfunctional (meth)acrylate monomer having a molecular weight of 175 to 1000 and a thermoplastic resin having a weight average molecular weight of 10000 to less than 100000, and the mass ratio of the polyfunctional (meth)acrylate monomer and the thermoplastic resin in the resin composition is 10:90 to 75:25, the decorative sheet has contamination resistance with respect to sunscreen creams, and moldability.
The technique described in Patent Document 1 is useful in production of a decorative sheet having excellent moldability and chemical resistance, but these days, consumers' demands for decorative resin molded articles are advanced and diversified, and for following these demands, creation of a new technique for imparting excellent moldability and chemical resistance to a decorative sheet is required.